Process of cooling and liquefying gases.



G. HILDBBRANDT.

PROCESS FOR COOLING AND LIQUEFYING GASES.

APPLICATION FILED DEC. 4, 1907.

Patented June 28, 1910.

a specification.

GOTTHOLD HILDEBRANDT, OF BERLIN, GERMANY.

PROCESS FOR COOLING AND. LIQUEFYING GASES.

962,836. Specification of Letters Patent. Patented J 11119 28, 1910,

Application filed December 4, 1907. I Serial No. 405,124,

drawal of the carbonic acid gas or mechanical means is-avoided.

The improved method can be carried out in various ways, the use of particular forms of apparatus, but one suitable construction is illustrated by Way of example in the accom anying drawing.

. The-mixture, which fbr the .sake of example may be assumed to consist of air and carbonic acid gas, is first compressed in'a compressor A, and after the compressed gas has been passed through a water or other cooler A in order to withdraw the heat of compression from it, the compressed gas passes through the coils of a prelimi nary cooler B and separates in the collector C,'the carbonic acid which is liquefied before the air is liquefied. This separated and liquefied carbonic acid is allowed to expand in the vessel D which surrounds the reliminary cooling apparatus B, and the air from which the carbonic acid has been separated passes from the top of the vessel C through another cooling or'heat-exchanging apparatus E, and then is allowed to expand in the chamber F in which it is liquefied, and collected as at G. Any air remaining unliquefied surrounds the heat-exchanging device E and then escapes into the atmosphere or into another chamber.

The addition of the gases of higher boiling point can be efl'ected in any convenient way. In the example illustrated, the outlet of the evaporating chamber D for the carbonic acid gas can be connected to the suction valve of the compressor pump, and the pipe constituting the said connection is provided'with an air-suction valve H so that at every stroke of the piston fresh air containing'a small proportion of new free car.- bonic acid gas can be drawn in together with the carbonic acid expanded in the chamber D.

In arranging the apparatus care is taken that the liquefaction of the gas with the higher boiling point takes place in such a part of the apparatus that it cannot freeze and obstruct any pipe or other passage.

What I do claim, and desire to secure by Letters Patent is- 1. The hereinbefore described process of cooling. and liquefying a gas havmg a relatively low boiling polnt, consisting in first mixing the said boiling point w1th another gas havlng a relatively high boiling point, then com- To all whom it may concern:

Be it known that I, Gor'rHoLn HILDE- BRANDT, a subject of the Emperor of Germany, residing at Berlin, Germany, have. invented an Improved Process for Cooling and Liquefying Gases, of which the following is by chemical his invention relates to the cooling and liquefying of gases and apparatus therefor. Gases which are difiicult to liquefy, such as oxygen, nitrogen, etc., when cooled by means of the expansion of gases which are easier to liquefy, such, for example, as ammonia, carbonic acid (G0,), etc. For this reason refrigerating machines worked by means of ammonia, carbonic acid gas, etc., have proved in practice superior to refrigerating machines worked with air. In the cooling and liquefying of gases which are ditficult to liquefy, i. e., which have a very low boiling point, it has been proposed to use in addition to machinery for liquefying by means of air, separate refrigerating machinesuworked. with ammonia or carbonic acid gas in order to effect the preliminary cooling of the compressed air in a cheaper and more eflicient manner than would have been possible by the use simply of the compression, watercooling and expansion of the air. This arrangement has the drawback of necessitating addltional ma chinery involving greater inltial expense and more supervision. According to this invention this disadvantage is obvlate'd by mixing with the gas of very low boiling point, a gas with a higher boiling point, compressing the mixture and after removal of the heat of compression, lique fying the gas of higher boiling point at an earlier stage than that at which the liquefaction of the gas with the lower boiling point takes place, such lique-. fied gas being then allowed to'expand and assist in the liquefaction of the gas with the low boiling point or to cool a further supply of the mlxed gas.

ere the gas to be treated is already in the form of a mixture of gases having diflerent boiling points, as for example in dealing with atmospheric air which always contains a proportion of carbonic acid gas, the presence of the gas of comparatively high boiling point is utilized in this way, and the expense and trouble of the preliminary withand is not dependent on gas having a relatively low 9 962,336 pressing the mixture of said gases, then remitting the same toexpand to be utilized in moving the heat of compression from the assisting in liquefylng the said gas having said mixtureof gases and then liquefying the said gas having the relatively high boile ing point and permitting the same to expand to be utilized 'n other cooling processes.

2. The hereinbefore described process for cooling and liquefying a gas having a relatively low boiling polnt, consisting in first mixing the said gas havinga relatively low boilin point with a gas having a relatively high oiling point, then compressing the said mixture of gases, then removing the heat of compression from the said mixture of gases and then liquefying the said gas having the relatively high boiling point and ermitting the same to expand to be utilized in assisting in liquefying the said gas having the relatively low boiling point.

3. The hereinbefore descrlbed process for cooling and liquefying a gas having a relativelylow bo1l1ng point, consisting in first mixing the said gas having a relatively lOW boilin oint with a gas having a relatively high oiling point, then compressing the said mixture of gases, then removing the heat of compression from the said mixture of gases, then liq uefying the said gas having the relatively high bol ing point and perthe relatively low boiling) point, said as having a relatively high oiling point eing maintained in the cycle of the process.

4. The hereinbefore described process for cooling and liquefying gases having low boiling points, consisting in first mixing a gas having a relatively low boiling point with a gas having a relatively high boiling point, then compressing the mixture of said gases, then removing the heat of compression from the said mixture of gases and then liquefying the said gas having a relatively high boiling point and permitting the same to expand to be utilized in assisting in the liquefaction of the gas having the relatively low boiling point, the liquefaction of the said ases. taking place in separate stages and t e liquefaction of the gas of the relatively high boiling point occurring in such a stage of the process that the temperature thereof is sufiiciently high to prevent it from freezin Signed by me this 21st GOTTHOLD HILDEBRANDT. Witnesses:

HENRY HASPER, WOLDEMAR Haor'r.

ay of November 

